Investigation of phenol electrooxidation in aprotic non-aqueous solvents by using cyclic and normal pulse voltammetry

Abstract

Electrooxidation of phenol was studied on platinum electrode in five aprotic nonaqueous solvents (acetonitrile, dimethyl sulfoxide, dimethyl formamide, acetone, and tetrahydrofuran) with cyclic and normal pulse voltammetry. The cyclic voltammetric results showed that fouling of the electrode surface by the polyphenol took place continuously in dimethyl formamide and a weak passivation of the electrode could be observed in dimethyl sulfoxide. From this solvent, a coherent and mechanically removable, weakly adsorbed layer could be obtained. In the other three solvents, the electrode passivated completely after five scans. Diffusion barrier properties of the polymer formed in acetone were the most pronounced of all solvents towards a redox probe. Normal pulse voltammetric investigations showed that the extent of electrode passivation is insignificant in three of the solvents used. It was due to the application of the short anodic potential pulses where the oxidation of phenol occurred and the formed oligomers diffused into the bulk of solution.

Effect of Anodic Pretreatment on the Performance of Glassy Carbon Electrode in Acetonitrile and Electrooxidation of Para-substituted Phenols in Acetonitrile on Platinum and Glassy Carbon Electrode

“…In some earlier works phenol showed quick fouling in acetonitrile on platinum and indium tin oxide electrodes [15,16]. In an earlier work electrooxidation of phenol was investigated on platinum electrode with cyclic voltammetry between 0 and 2 V which fouled quickly due to the formation of a coherent poly(phenyleneoxide) on its surface [12]. In order to see the electrooxidation of phenol on glassy carbon electrode five repetitive cyclic voltammograms were taken in acetonitrile also with it between 0 and 2 V ( Fig.…”

“…It is generally observed that most of one hydroxyl group containing phenols deactivate the surface of commonly used electrodes in most of the solvents [7][8][9][10][11][12][13][14]. It is interesting in many respects for example electrodes can be modified according to the application like size exclusion properties and corrosion protective layers.…”

Electropolymerization of N,N'-Diphenylguanidine in Non-Aqueous Aprotic Solvents and Alcohols

“…The permeability results show that most of the obtained films can release molecules with large flux. The compactness of polyphenol layers investigated in earlier works [28,29] 1-butanol, E) 1-pentanol, F) benzyl alcohol; supporting electrolyte 50 mM TBAP, v=0.1 V/s were more significant than that of electropolymerized N,N'diphenylguanidine in the same solvents. The only exception is dimethyl sulfoxide due to the low degree of deactivation and regarding the alcohols the permeability of film formed in methanol was remarkably high.…”

“…In two recent works, phenol was studied by using voltammetric methods in alcohols and aprotic non-aqueous solvents [28,29]. The main findings concerning the used solvents will be summarized here in some words which is important by studies with N,N'-diphenylguanidine.…”

“…By the same supporting electrolyte concentration, the voltammograms of the selected aprotic solvents were also taken in an other work [29]. It was demonstrated that none of them had any peak in their voltammogram.…”